US3898102A - Bipolar low-pressure electrode for gas fuel cells - Google Patents

Bipolar low-pressure electrode for gas fuel cells Download PDF

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Publication number
US3898102A
US3898102A US343477A US34347773A US3898102A US 3898102 A US3898102 A US 3898102A US 343477 A US343477 A US 343477A US 34347773 A US34347773 A US 34347773A US 3898102 A US3898102 A US 3898102A
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United States
Prior art keywords
gas
foil
active electrode
layer
electrode layer
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Expired - Lifetime
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US343477A
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English (en)
Inventor
Gerhard Louis
Harald Bohm
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Licentia Patent Verwaltungs GmbH
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Licentia Patent Verwaltungs GmbH
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Priority claimed from DE19722214412 external-priority patent/DE2214412C3/de
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/8605—Porous electrodes
    • H01M4/8626—Porous electrodes characterised by the form
    • H01M4/8631—Bipolar electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • each active electrode layer is provided with raised portions which, together with the adjoining foil face, define a channel system form ing a closed gas chamber.
  • the raised portions are so arranged that the gas which enters and leaves the gas chamber through an inlet opening and an outlet opening provided in the active electrode layer is substantially evenly distributed over the entire area of the gasside face of the active electrode layer.
  • Bipolar electrodes for alkaline and acid fuel cells are known in the art.
  • the gas chamber and the contacting separator wall are frequently formed by metallic components having the configuration of a corrugated sheet.
  • bipolar lowpressure electrodes operating in acid electrolytes such a solution is not feasible. since there are no contact metals available which would be suitable from an eco nomical point of view.
  • fuel cells containing an acid electrolyte it is known to form the gas chamber and the contacting separator wall (cell wall) by a bilaterally ribbed plate which is made either of sintered ceramic rendered conductive by mixing thereto gold particles or by a rigid electrographite having a contacting anode and cathode applied to opposite faces.
  • the electrode For the purpose of introducing and distributing the gas fuel, the electrode has an open channel system formed of parallel webs extending over the entire width of the electrode.
  • the gas enters the channel system at one side of the electrode, then it is guided lengthwise by the parallel webs and eventually it is taken out at the opposite side of the electrode.
  • large slots are provided for the intake and outlet of the gas.
  • the aforeoutlined design preconditions that the inlet and outlet slots merge into wide supply channels which have to be provided additionally at the outside of the battery. These channels significantly increase the overall volume of the battery.
  • the electrode comprises a flexible graphite foam foil to which there are bilaterally applied active electrode layers that leave a free edge zone at the foil and which, at the gas side. are provided with a channel system constituting a closed gas chamber.
  • the channel system is formed by raised portions provided on the gas-side face of each active layer. The latter have throughgoing openings to constitute an access for the air and the fuel gas to the gas chamber.
  • FIGS. la and lb are side elevational views of oppo site faces of an electrode according to the invention.
  • FIG. 2 is a side elevational view of a component forming part of the electrode and shown in the absence of an active electrode layer thereon.
  • FIG. 3 is a side elevational view, from the gas side, of an active electrode layer.
  • FIG. 4 is a side elevational view, from the gas side, of another embodiment of an active electrode layer.
  • the bipolar electrode comprises an electronically contacting flexible foil I which separates gas and electrolyte from one another and which is formed of a strong graphite foam of approximately 0.2 millimeter thickness.
  • anode layer 2 and two sealing elements 3 and 4 To one side of the foil there is applied an anode layer 2 and two sealing elements 3 and 4 (FIG. 1a) while on its other side there is provided a cathode layer 5 and two sealing elements 6, 7 (FIG. lb).
  • each layer 2, 5 is smaller than that of the corresponding face of the graphite foam foil I so that a free foil margin 8 is obtained which provides a surface for an electrolyte-tight, elastic clamping of the electrode layers 2, 5 while leav ing the edge zones of the latter free.
  • the electrolyte (not shown) is in contact with the outer faces of the layers 2. 5.
  • the anode layer 2 is made, for example. of tungsten carbide with polytetrafluoroethylene (PTFE), while the cathode layer is made, for example, of activated carbon with PTFE.
  • the sealing elements 3, 4 with the holes 9, 10 provided in the foil I serve as a coupling for the air supply to the next electrode while the sealing elements 6, 7 with the holes II, I2 provided in the foil I function as a coupling for the gas fuel supply to the next electrode.
  • the anode layer 2 has inlet and outlet openings I3 and [4 which are in alignment with the respective holes II and 12 while the cathode layer 5 has inlet and outlet openings I5, I6 that are in alignment with the holes 9. It).
  • the anode layer 2 is in a face-to-face engagement with the graphite foam foil I while overlapping the holes I], I2 but circumventing the sealing elements 3. 4.
  • the cathode layer 5 is in a face-to-face engagement with the graphite foam foil I while overlapping the holes 9. 10 but circumventing the sealing elements 6. 7.
  • An electronically conducting bond between the anode layer 2, the cell wall and the cathode layer 5 may be effected. for example. by gluing these components together with a two-component hardenable resin under a pressure of approximately 100 kp/cm or by means of synthetic material sintering under pressure.
  • the graphite foam foil 1 which is illustrated in FIG. 2 in the absence of the active electrode layer, serves, in addition to its function a cell wall. for the transmission of current from one layer to the other.
  • the graphite foam foil 1 By means of the graphite foam foil 1 there is achieved a direct, large-surface contacting between the anode 2 and the cathode S. In this manner, extremely short current paths are obtained which are of particular significcance in fuel cells having acid electrolyte, because for such fuel cells no technically satisfactory contacting and current conducting materials are available. Such materials, for the purpose of obtaining light-weight components with small ohmic losses should have a very good conductivity.
  • the design according to the invention thus makes it possible to use materials of lesser conductivity by using as large-surface electrodes without current carrying elements, catalyst layers that are bound by a synthetic material.
  • the anode layer 2 and cathode layer 5 are attached to one another by the graphite foam foil 1.
  • the electrode is secured by engagement of the margin 8 of the graphite foam foil 1 and thus, consequently, the electrode layers 2, 5 do no longer have to be clamped at their edges.
  • the holding means for the margin 8 may be provided either by glu ing it into a frame or by pouring on the foil 1 an appropriate immobilizing material with the aid of appropriate seals or solely by mechanical clamping.
  • the graphite foam foil 1 has the following functions: I. it is a dividing cell wall separating the electrolytes from cell to cell;
  • FIG. 3 shows the gas-side face of the anode layer 2.
  • FIG. 3 shows the anode layer 2 separated from the foil 1 to render the gas-side face of the anode layer 2 visible.
  • the gas-side face is thus oriented toward the graphite foam foil I as opposed to the electrolyte-side face which is oriented away from the foil 1 and which is visible in FIG. la.
  • the other active electrode layer that is, the cathode layer 5 which is of a structure identical to that of the anode layer 2.
  • the anode layer 2 has an elevated, continuous perimetric edge 29 which is bonded to the graphite foam foil l. Although the latter differs from the active layers regarding the coefficients of expansion. but since both layers are made of a highly porous elastic skeleton structure. even in case of substantial temperature fluctuations no harmful stresses appear between the bonded layers 1. 2. 5.
  • An improved strength of the electrode layers 2 and 5, as well as a superior protection against shortcircuiting within the battery may be chieved by providing the electrode faces with sintered-on non-woven glass fiber or similar fibrous insulating material.
  • the two electrode layers 2 and 5 operate as gas diffusion electrodes and are, together with the graphite foam foil I, utilized to form a gas-guiding channel system.
  • the electrode layers 2, 5 have, at their face oriented towards the foil 1 that is, on their respective gas-side face raised portions (such as webs or ribs) 17 which project in the same direction and have the same height as the perimetric edge 29.
  • the gas is situated between the graphite foam foil 1 and the electrode layer 2.
  • the channel system which communicates with the two diagonally oppositely located inlet and outlet openings 13, 14 of the anode layer 2 ensures a uniform distribution of the gas flow over the entire electrode face and also provides, between the two openings 13, I4, a gas flow over the electrode surface without appreciable loss of pressure. In low-pressure electrodes this feature is of primary importance concerning the operation of large-surface electrodes that utilize air and fission gases since the latter, due to the high proportion of inert gas, require a substantial flow for effecting removal thereof.
  • the same type of raised portions provided at the gas side of the anode layer 2 is also present on the gas-side face of the cathode layer 5.
  • the arrangement of the raised portions on both electrode layers 2 and 5 is identical. Consequently. the graphite foam foil is on each side engaged by exactly aligned webs, so that when the electrode lay ers 2 and 5 are bonded under pressure to the graphite foam foil 1, a slippage or deformation of the foil 1 will not occur.
  • the raised portions ]7 effect a uniform distribution of the gas flow.
  • the gas would flow from the inlet I3 diagonally to the outlet 14 so that large portions of the gas side face 18 of the anode layer 2 would not be contacted by the gas.
  • the raised portions I7 ensure that the gas is distributed uniformly over the entire gasside face I8 of the anode layer 2.
  • the gas is constrained to follow paths along the face of the electrode layer other than a diagonal direction, since the flow resistances are practically identical along a number of paths from the inlet 13 to the outlet I4.
  • the above-mentioned intermediate webs have varying lengths and further they are staggered with respect to one another in accordance with a predetermined design. In this manner there are obtained different flow resistances and a corresponding distribution of the gas.
  • the intermediate webs of the rows 23 and 24 are relatively short in order to ensure a fine distribution of the gas flow.
  • the lengths of these webs are designed in such a manner that. together with the webs 27 which contribute only slightly to the uniformity of the gas flow. they cause the gas passing through the webs of the row 23 to split up and arrive as individual streams into the channels formed by the webs 27.
  • the guide webs 19 arranged at the inlet 13 direct the gas in partial flows in the direction of the rows 21-23 over the face 18 of the layer 2.
  • the intermediate webs of the rows 21-23 effect a further division of the partial flows and also cause a deflection of these flows of approximately 90 so that the entire zone 28 of the face 18 is covered by gas.
  • the parallel and identically long webs 27 have the primary function of giving the electrode sufficient stability and to provide a contacting means.
  • the webs 27 participate in rendering the gas flow uniform, they are not essential for guiding the gas streams.
  • the raised portions [7 have two functions: first. they provide for the uniform gas distribution and second, they provide for a uniform contacting of the electrode layer 2 and the cell wall I which, because of the highly ohmic characteristics of the materials is also of significance.
  • the anode layer 2 has at its gas-side face 18 raised portions constituted by a great number of dotlike bosses 30.
  • the boss grid formed in this manner has zones 31, 32, 33 and 34 in which the bosses 30 are arranged closer to one another (greater density of boss distribution) so that in these zones higher flow resistances are generated. In this manner it is ensured that the gas flow will not prefer a diagonal direction. It is seen that the boss groups 31 and 32 are located in the vicinity of gas outlet 14 and gas inlet 13, respectively, while the boss groups 33, 34, 35 are located in a middle zone of the entire boss grid. The flow resistances are varied in such a manner that a flow distribution is also effected in the edge zones of the face 18.
  • the advantages accomplished by the invention reside particularly in that the power/weight ratio of the fuel cell batteries is optimized by virtue of a direct, largesurface contacting of the anode of one cell with the cathode ofthe successive cell. No external electric connections or the associated current conductors of the individual electrode are needed. Particular currentcarrying conductor elements are also not required.
  • the positioning of the gas inlets and outlets in the active layers of the electrode permits a suspension of the layers without engaging an edge zone thereof.
  • the electrode layers may be manufactured in a simple one-step operation during which the raised portions for forming the channel system may also be provided. Thus, the channel system is obtained without requiring additional material or time.
  • the channel system By virtue of the particular shape of the channel system there is obtained a very small flow resistance so that the gas may flow without appreciable pressure loss over the entire gas-side face of the electrode layer, By virtue of the elastic securing of the electrode layers to the graphite foam foil, the latter may op erate without mechanical damage which is of great significance with regard to its life expectancy and assem bly considerations.
  • a bipolar low-pressure electrode for gas fuel cells comprising in combination:
  • a. a fiexible flat graphite foam foil having two opposite faces and being provided with holes for the passage of air and for the passage of fuel gas;
  • an active electrode layer secured in a face-toiace, electronically contacting relationship directly to each face of said foil, each active electrode layer having a gas-side face oriented towards said foil; one active electrode layer being an anode and the other active electrode layer being a cathode; said holes for the passage of air being situated within the outline of the cathode layer and externally of the outline of the anode layer; said holes for the passage of fuel gas being situated within the outline of the anode layer and externally of the outline of the cathode layer;
  • each active electrode layer c. a continuous, elevated perimetric edge forming part of each active electrode layer and being in direct contact with and being bonded to said foil for forming an enclosed space between said gas-side face of the active electrode layer and the adjoining face of said foil, said enclosed space constituting a closed gas chamber;
  • first sealing means in engagement with said foil adjacent said anode layer, said first sealing means surrounding said holes for the passage of air;
  • each face of said foil includes a free marginal zone extending externally of the perimeter of said active electrode layer, said zone being free from said throughgoing openings and is constituted by an entirely uninterrupted surface.
  • a third group disposed spaced from said second (ill group for combining said partial flows into a decreased number of streams and deflecting the latter in the direction of the outlet opening of the active electrode layer whereby the gas flowing from the inlet opening to the outlet opening is substantially uniformly distributed over the entire gas-side face of the active electrode layer,

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Fuel Cell (AREA)
US343477A 1972-03-24 1973-03-21 Bipolar low-pressure electrode for gas fuel cells Expired - Lifetime US3898102A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19722214412 DE2214412C3 (de) 1972-03-24 Bipolare Niederdruckelektrode für Gasbrennstoff batterien

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US3898102A true US3898102A (en) 1975-08-05

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US343477A Expired - Lifetime US3898102A (en) 1972-03-24 1973-03-21 Bipolar low-pressure electrode for gas fuel cells

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US (1) US3898102A (sv)
JP (1) JPS4913637A (sv)
BE (1) BE797095A (sv)
FR (1) FR2177905B1 (sv)
GB (1) GB1416369A (sv)
NL (1) NL7304009A (sv)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4188464A (en) * 1978-07-31 1980-02-12 Hooker Chemicals & Plastics Corp. Bipolar electrode with intermediate graphite layer and polymeric layers
US4246324A (en) * 1979-04-09 1981-01-20 Diamond Shamrock Technologies S.A. Consumable replaceable anodes for batteries
US6171374B1 (en) 1998-05-29 2001-01-09 Ballard Power Systems Inc. Plate and frame fluid exchanging assembly with unitary plates and seals
WO2008156647A1 (en) * 2007-06-15 2008-12-24 Bloom Energy Corporation Dot pattern contact layer
US20100316931A1 (en) * 2009-06-10 2010-12-16 Friedrich Wilhelm Wieland Electrocatalyst, Fuel Cell Cathode and Fuel Cell

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2302600A1 (fr) * 1975-02-25 1976-09-24 Inst Francais Du Petrole Nouveau perfectionnement aux piles a combustible
FR2432774A1 (fr) * 1978-07-31 1980-02-29 Inst Francais Du Petrole Electrode creuse pour pile a combustible
JPS57114497U (sv) * 1981-01-07 1982-07-15
JPS57115772A (en) * 1981-01-08 1982-07-19 Meidensha Electric Mfg Co Ltd Liquid circulation type laminated cell
JPS5871570A (ja) * 1981-10-26 1983-04-28 Agency Of Ind Science & Technol 金属―臭素電解液循環型積層２次電池
CA1259101A (en) * 1984-04-09 1989-09-05 Hiroyuki Fukuda Carbonaceous fuel cell electrode substrate incorporating three-layer separator, and process for preparation thereof
FR2564250B1 (fr) * 1984-05-11 1986-09-12 Alsthom Atlantique Ameliorations aux structures des piles a combustible
FR2564251B1 (fr) * 1984-05-11 1986-09-12 Alsthom Atlantique Perfectionnements aux structures des piles a combustible
US4794043A (en) * 1985-04-30 1988-12-27 Kureha Kagaku Kogyo Kabushiki Kaisha Carbon product comprising carbonaceous materials joined together, said carbon product for electrode substrate of fuel cells and process for production thereof
US4818640A (en) * 1985-09-25 1989-04-04 Kureha Kagaku Kogyo Kabushiki Kaisha Carbonaceous composite product produced by joining carbonaceous materials together by tetrafluoroethylene resin, and process for producing the same
JPS6282663A (ja) * 1985-10-04 1987-04-16 Kureha Chem Ind Co Ltd マニホ−ルド付燃料電池用電極基板及びその製造方法
JP2569540B2 (ja) * 1987-03-30 1997-01-08 石川島播磨重工業株式会社 燃料電池用セパレ−タ
JP4507650B2 (ja) * 2004-03-15 2010-07-21 トヨタ自動車株式会社 燃料電池
US20060093891A1 (en) * 2004-11-02 2006-05-04 General Electric Company Flow field design for high fuel utilization fuel cells

Citations (5)

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Publication number Priority date Publication date Assignee Title
US3188242A (en) * 1959-01-22 1965-06-08 Union Carbide Corp Fuel cell battery containing flat carbon electrodes
US3413239A (en) * 1966-03-03 1968-11-26 Dow Chemical Co Vermicular graphite structures and method of making
US3416965A (en) * 1963-08-09 1968-12-17 K W Battery Company Fuel cell including chlorite containing electrolyte and method of operation
US3533847A (en) * 1967-02-23 1970-10-13 United Aircraft Corp Fuel cell assembly
US3690954A (en) * 1970-03-02 1972-09-12 Alsthom Cgee Fuel cell and electrolyte supply system

Family Cites Families (1)

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NL129942C (sv) * 1961-05-08 1900-01-01

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3188242A (en) * 1959-01-22 1965-06-08 Union Carbide Corp Fuel cell battery containing flat carbon electrodes
US3416965A (en) * 1963-08-09 1968-12-17 K W Battery Company Fuel cell including chlorite containing electrolyte and method of operation
US3413239A (en) * 1966-03-03 1968-11-26 Dow Chemical Co Vermicular graphite structures and method of making
US3533847A (en) * 1967-02-23 1970-10-13 United Aircraft Corp Fuel cell assembly
US3690954A (en) * 1970-03-02 1972-09-12 Alsthom Cgee Fuel cell and electrolyte supply system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4188464A (en) * 1978-07-31 1980-02-12 Hooker Chemicals & Plastics Corp. Bipolar electrode with intermediate graphite layer and polymeric layers
US4246324A (en) * 1979-04-09 1981-01-20 Diamond Shamrock Technologies S.A. Consumable replaceable anodes for batteries
US6171374B1 (en) 1998-05-29 2001-01-09 Ballard Power Systems Inc. Plate and frame fluid exchanging assembly with unitary plates and seals
WO2008156647A1 (en) * 2007-06-15 2008-12-24 Bloom Energy Corporation Dot pattern contact layer
US20090075125A1 (en) * 2007-06-15 2009-03-19 Bloom Energy Corporation Dot pattern contact layer
US20100316931A1 (en) * 2009-06-10 2010-12-16 Friedrich Wilhelm Wieland Electrocatalyst, Fuel Cell Cathode and Fuel Cell

Also Published As

Publication number Publication date
NL7304009A (sv) 1973-09-26
GB1416369A (en) 1975-12-03
FR2177905A1 (sv) 1973-11-09
JPS4913637A (sv) 1974-02-06
DE2214412A1 (de) 1973-10-04
FR2177905B1 (sv) 1978-08-04
DE2214412B2 (de) 1975-10-16
BE797095A (fr) 1973-07-16

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